Audible alarm device

ABSTRACT

A piezoelectric transducer is utilized in conjunction with a tone generator, a pulsator means, and a transient protection means to produce an audible alarm in response to various input electrical signals.

[451 Nov. 25, 1975 United States Patent 91 Birt et al.

[56] References Cited UNITED STATES PATENTS AUDIBLE ALARM DEVICEInventors: Thomas W. Birt, Indianapolis; Louis 340/384 E Shoey 340/384 ELocke 340/384 R Denning..........,...............

24 777 0 90 ill //I 005 969 766 860 t 333 lndlanapohs PrimaryExaminer-John W. Caldwell Mar. 4, 1974 Appl. No.: 447,861

Assistant Examiner-William M. Wannisky [22] Filed:

Attorney, Agent, or Firm-Charles W. Hoffmann; Robert F. Meyer; Donald W.Hanson [57] ABSTRACT A piezoelectric transducer is utilized inconjunction [52] US. 340/384 E; 340/384 R; 331/64;

with a tone generator, a pulsator means, and a transient protectionmeans to produce an audible alarm in response to various inputelectrical signals.

9 Claims, 1 Drawing Figure o a i t i i a u .unt a V. 5 1 w M W o 1i .l|N v\ m a 2M r [so i l Us m H m. a mo w Nov. 25, 1975 U.S. Patent AUDIBLEALARM DEVICE Generally speaking the present invention relates to anaudible alarm device comprising a tone generator means including apiezoelectric transducer, a pulsator means connected to the tonegenerator means, a transient protection means connected to the pulsatormeans and the tone generator means, and an input-output terminal meansconnected to the transient protection means and to the tone generatormeans. he The Embodiments of the present invention may be utilized inmany applications where an audible alarm is required. The illustratedembodiment of the present invention is adapted to provide a variety ofaudible alarm sounds in response to electrical signals produced withinan automobile. For example, this embodiment can provide one tone toindicate that seat belts are not fastened, another tone to remind thedriver that his keys are in the ignition when he opens a door, andanother tone to warn the driver that the is speeding. the tones may becontinuous or pulsing.

Audible alarm devices are well known in automobile applications to warna driver of a potential problem or alert him of a situation requiringimmediate attention. Many of these alarms are in the form ofelectromagnetic buzzers, and one buzzer is normally required for eachwarning signal required. In recent years, more and more warnings arebeing required in automobile applications.

Locating several buzzers in a car can be difficult. For a driver torecognize one buzz from another, the buzzers are sometimes separated sothat, for example, a speedometer speed warning signal comes from hisleft and a fasten seat belt signal can be heard from his right. Thepresent invention eliminates this location problem by providing onealarm device centrally located. The transducer signals, each indicatinga different warning, are distinguishable because they differ in rate ofpulsing.

Another problem associated with electromagnetic buzzers is theirinherently unpleasant sound. This buzzer noise is sometimes a dangerousdistraction to a driver of an autombile. The present invention solvesthis problem by utilizing a piezoelectric transducer which produces apleasing audible tone.

Another problem involved with locating a number of electromagneticbuzzers, each for a different signal, throughout an automobile is thecost of the wiring to each of the buzzers, the cost of installationlabor, and the cost of the necessary support equipment, such as electricconnectors and mounting brackets. The present invention provides apiezoelectric transducer audible alarm which, in an automobile mayreplace three electromechanical buzzers in one neat and very compactpackage a package that can be easily and quickly plugged into place orunplugged for service.

Accordingly, a feature of the present invention is to provide an audiblealarm device utilizing a piezoelectric transducer. Another feature ofthe present invention is to provide an audible alarm device including anintegrated circuit package. Another feature of the present invention isto provide an audible alarm device including a transient protectionmeans. Another feature of the present invention is to provide an audiblealarm device incorporating a Quad two-input NAND gate integrated circuitpackage. Another feature of the present invention is to provide anaudible alarm device for 2 use in an automobile to alert the driver tovarious situations requiring his attention.

These and other features will become more apparent from the followingdescription taken in conjunction with the accompanying drawing whereinthere is shown a wiring diagram of an embodiment of an audible alarmdevice utilizing a piezoelectric transducer and a Quad two-input NANDgate integrated circuit package.

Referring now to the drawing, an audible alarm device 10 comprises atone generator means 12, including a piezoelectric transducer 14, apulsator means 16 connected to tone generator means 12, a transientprotection means 18 connected to pulsator means 16 and tone generatormeans 12, an input-output terminal means 20 connected to transientprotection means 18, and a ground isolation means 22 connected to tonegenerator means 12, transient protection means 18, and input-outputterminal means 20.

Ground isolation means 22, for providing more than one ground path todevice 10, is connected directly to transient protection means 18 andinput-output terminal means 20 and also is connected through aresistance means 24 to both transient protection means 18 andinput-output terminal means 20.

Input-output terminal means 20 for providing electrical terminations tothe device 10 includes terminations 28, 30, 32, and 34. Termination 28is connected to ground isolation means 22, and a first side ofresistance means 24. Termination 30 is connected to voltage transientprotection means 18 and to a second side of resistance means 24.Termination 32 is connected to voltage transient protection means 18.Termination 34 is connected to voltage transient protection means 18 andground isolation means 22. A resistance means 26 is connected betweentermination 32 and 34.

Pulsator means 16 for producing pulsations in an audible toneincorporates two two-input NAND gates 36 and 38 of a Quad two-input NANDgate integrated circuit package 40. One such integrated circuit package40 is incased in a 14 terminal dual-in-line plastic module manufacturedby National Semiconductor Company of Santa Clara, Calif. An input 42 ofgate 36 is connected to voltage transient protection means 18, andanother input 44 of gate 36 is connected to a first side ofa resistancemeans 46. An input 47 of gate 38 is connected to voltage transientprotection means 18. Another input 48 of gate 38 is connected to a firstside ofa resistance means 50 and to an output 54 of gate 36. An output56 of gate 38 is connected to tone generator means 12 and to a firstside of a capacitance means 52. A second side of resistance means 46 isconnected to a second side of resistance means 50 and to a second sideof capacitance means 52.

Tone generator means 12 for producing an audible tone incorporates twotwo-input NAND gates 58 and 60 of the Quad two-input NAND gateintegrated circuit package 40. Piezoelectric transducer 14 includeselectrodes 62, and 76. Electrode 62 is connected to ground isolationmeans 22. An input 64 of NAND gate 58 and an input of NAND gate 60 areconnected to pulsator means 16. An input 66 of NAND gate 58 and an input78 of NAND gate 60 are connected to a first side of a resistance means68 and to electrode 70 of piezoelectric transducer 14. An output 72 ofNAND gate 58 and an output 82 of NAND gate 60 are connected to a secondside of resistance means 68 and through a resistance means 74 toelectrode 76 of transducer 14.

Ground isolation means 22 includes diodes 84 and 86. The anodes ofdiodes 84 and 86 are connected together and to the tone generator meansand to a minus voltage terminal 106 of integrated circuit package 40. Acathode of diode 84 is connected to termination 28 of input-outputterminal means 20 and through resistance means 24 to termination 30. Acathode of second diode 86 is connected to termination 34 and totransient protection means 18.

Transient protection means 18 for protecting device 10 againstelectrical transient voltages includes three resistance means 100, 102,103. Resistance means 100 is connected between termination 30 and input42 of first NAND gate 36. Resistance means 102 is connected betweentermination 32 and a plus voltage terminal 104 of integrated circuitpackage 40. Resistance means 103 is connected between termination 34 andinput 47 of second NAND gate 38.

A minus voltage terminal pin 106 of integrated circuit package 40 isconnected to electrode 62 of piezoelectric transducer 14 and to groundisolation means 22.

A typical application for audible alarm device 10 is an automobile toproduce audible signals to alert a driver to situations requiring hisattention. The FIG. illustrates a portion of a typical automobileelectrical circuit 88 connected to audible alarm device 10. A DC powersupply 90, which may comprise an automotive battery 92 is connectedpositive terminal 96 to termination 32 of circuit 10 and negativeterminal 98 to ground 94. Two single-pole single-throw switches SI and82 are connected in series between termination 30 of circuit l andpositive terminal 96 of DC power supply 90. Another single-polesingle-throw switch S3 is connected between termination 28 of circuit 10and ground 94. Two more single-pole single-throw switches 84 and S areconnected in series between termination 34 of circuit and ground 94. Asingle-pole singlethrow switch S6 is also connected between termination34 and ground 94.

In one application switches 81 through 86 may have these relationshipsto other automotive components: switch S2 is included in an ignitionswitch to be switched when the ignition switch is activated; switch S1is included in a gear shift lever so as to be switched in preselectedpositions of the lever such as drive; switch S3 is included in a seatbelt interlock module and is responsive to fastening or unfastening ofthe seat belt; switch S4 is incorporated in an ignition lock (separatefrom switch S2) to be switched upon insertion or withdrawal of ignitionkey; switch S5 is located in a passage doorway in such a manner as to beswitched upon opening and closing of the door; and switch S6 isincorporated in a speedometer to be switched at preselected positions ofa speedometer needle in relation to a speed scale dial.

in operation, termination 32 receives a positive voltage from powersupply 90. Termination also receives positive voltage from power supply90, but only upon the closing of switches S1 and S2. Termination 28becomes completed to ground 94 upon closing of switch S3. In thecondition wherein switches 81, S2 and 83 are closed, piezoelectrictransducer 14 emits a pulsating tone, the tone being produced by tonegenerator means 12 and the pulsations being produced by pulsator means16.

In pulsator means 16, first and second NAND gates 36 and 38 cooperatewith resistor 50 and capacitor 52 to cause the voltage at output 56 toalternately rise and fall in essentially a square wave manner at arepetition rate controlled by the values of resistor 50 and capacitor52. The pulsator circuit is enabled only when inputs 42 and 47 are at avoltage near the supply voltage.

NAND gates 58 and 60 cooperate with piezoelectric transducer in anoscillitory manner so that transducer 14 is excited into vibration nearits resonant frequency and sound is produced. Electrode of transducer 14provides a feedback voltage of a magnitude and phase to permit sustainedoscillations in the circuit. When the voltage supplied from output 56 ofNAND gate 38 to inputs 64 and of NAND gates 58 and 60 is near the supplyvoltage, oscillation will occur in tone generator circuit 12. Whenvoltage from output 56 is down or near ground potential the oscillationscease.

In the condition where switches 81, S2 and S3 are closed, pulsator means16 is enabled by receiving a pos itive voltage at input 42 of NAND gate36, (the input 47 of gate 38 is held at a positive voltage throughresistors 26 and 103 so that the pulsator may be enabled by input 42)and a pulsating tone is emitted by piezoelectric transducer 14. In thecondition where switch S6 or both switches 84 and S5 are closed, therebyconnecting termination 34 to ground, pulsator means 16 is disabledthrough input 47 of NAND gate 38. This allows tone generator means 12 torun continuously thereby causing transducer 14 to emit a continuoustone.

What is claimed is:

I. An audible alarm system comprising in combination.

a. an input-output terminal means for providing electrical terminationsfor attaching electrical circuits;

b. a transient protection circuit for protecting said audible alarmsystem against voltage transients and having an input side connected tosaid input-output terminal means, and an output side;

c. a tone generator circuit for producing an audible tone and having aninput side and an output side including a piezoelectric transducerconnected to said input-output terminal means; and

d. a pulsator circuit for producing pulsations in said audible tonecomprising:

1. a first NAND gate section of a Quad two-input NAND gate integratedcircuit package, a first input connected to said output side of saidtransient protection circuit, and a second input connected to one sideof a first resistance means;

2. a second NAND gate section of a Quad twoinput NAND gate integratedcircuit package, a first input connected to said output side of saidtransient protection circuit, a second input connected to an output ofsaid first NAND gate section and to a first side of a second resistancemeans, and an output of said second NAND gate section connected to saidinput side of said tone generator circuit and to a first side of acapacitance means; and

3. a second side of said first resistance means connected to a secondside of said second resistance means and to a second side of saidcapacitance means 2. A multiple audible alarm system comprising incombination.

a. an input-output terminal means for providing electrical terminationfor attaching electrical circuits;

b. a transient protection circuit for protecting said audible alarmsystem against voltage transients and having an input side connected tosaid input-output terminal means, and an output side;

c. a tone generator circuit for producing an audible tone and having aninput side and an output side including a piezoelectric transducerconnected to said input-output terminal means; and

d. a ground isolation circuit providing more than one ground path tosaid multiple audible alarm system, a first side connected directly tosaid input-output terminal means, a second side connected directly tosaid input side of said transient protection circuit and to saidinput-output terminal means, and also to said input side of saidtransient protection circuit and to said input output terminal meansthrough a first resistance means, and a third side connected to saidinput side of said tone generator circuit;

whereby said piezoelectric transducer provides pulsating sounds orcontinuous sounds in response to a precondition of said multiplefunction alarm system.

3. A multiple function alarm system according to claim 2 wherein saidtone generator circuit further includes at least one NAND gate, saidNAND gate and said pulsator circuit included as an integrated circuitpackage and wherein said third side of said ground isolation circuit isconnected a minus voltage terminal of said integrated circuit packageand to said piezoelectric transducer.

4. A multiple function alarm system according to claim 3 wherein saidpulsator circuit includes two NAND gates.

5. A multiple audible alarm system according to claim 2 wherein saidinput-output terminal means includes:

a. a second termination connected to said third side of said groundisolation circuit;

b. a second termination connected to said input side of said transientprotection circuit and also through said first resistance means to saidfirst termination;

c. a third termination connected to said input side of said transientprotection circuit; and

d. a fourth termination connected to said of said transient protectioncircuit, said second side of said ground isolation circuit, and alsothrough a second resistance means to said third termination.

6. A multiple audible alarm system according to claim 2 wherein saidpulsator circuit comprises:

a. a first NAND gate section of a Quad two-input NAND gate integratedcircuit package, a first input connected to said output side of saidtransient protection circuit, and a second input to one side of a thirdresistance means;

b. a second NAND gate section of a Quad two-input NAND gate integratedcircuit package, a first input connected to said output side of saidtransient protection means, a second input connected to an output ofsaid first NAND gate section and to a first side of a fourth resistancemeans, and an output of said second NAND gate section connected to saidinput side of said tone generator circuit and to a first side of a firstcapacitance means; and

c. a second side of said third resistance means connected to a secondside of said fourth resistance means and to a second side of said firstcapacitance means.

7. A multiple audible alarm system according to claim 2 wherein:

said piezoelectric transducer has three electrodes, a

first electrode of which is connected to said third side of said groundisolation circuit and said minus voltage terminal of a Quad two-inputNAND gate integrated circuit package; and wherein said tone generatorcircuit further includes:

a. a third NAND gate section of said Quad twoinput NAND gate integratedcircuit package, a first input connected to said output side of saidpulsator circuit, a second input connected to a first side of a fifthresistance means and to a second electrode of said piezoelectrictransducer, an output connected to a second side of said fifthresistance means and to a first side of a sixth resistance means;

b. a fourth NAND gate section of said Quad twoinput NAND gate integratedcircuit package, a first input connected to said first input of saidthird NAND gate section, a second input connected to said second inputof said third NAND gate section, and an output connected to said outputof said third NAND gate section; and a second side of said sixthresistance means connected to a third electrode of said piezoelectrictransducer.

8. A multiple alarm system according to claim 2 wherein said groundisolation circuit includes first and second diodes, the anodes of whichare connected together and to said output side of said tone generatorcircuit and said minus voltage terminal, the same being a terminal of aQuad two-input NAND gate integrated circuit package, a cathode of saidfirst diode connected to a first termination of said input-outputterminal means and through a first resistance means to a secondtermination of said input-output terminal means, and a cathode of saidsecond diode connected to said fourth termination of said inputoutputterminal means, through a second resistance means to a third terminationof said input-output terminal means, and to said input side of saidtransient protection circuit.

9. A multiple audible alarm system according to claim 2 wherein saidtransient protection circuit comprises seventh, eighth and ninthresistance means, said seventh resistance means connected between saidfourth termination and said input side of said pulsator circuit, saideighth resistance means connected between said third termination and apositive voltage terminal of a Quad two-input NAND gate integratedcircuit package, and said ninth resistance means connected between saidsecond termination and said input side of said pulsator circuit.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 72DATED 1 November 25, 1975 INVENTOR(S) I Bi t sweany and Pirtle it iscertified that error appears in the above-identified patent and thatsard Letters Patent are hereby corrected as shown below:

Col. 1 line 11, delete "he The" Col. 1, line 21 delete the secondoccurence "the" C01. 1, line 21 delete the third occurence "the" andsubstitute therefore The- Col. 5, line 53 insert "connected" afterinput.

Signed and Scaled this second D3) Of March 1976 [SEAL] Arrest:

RUTH c. MASON c. MARSHALL DANN Arlesting Officer Commissioner of Parentsand Trademarks

1. An audible alarm system comprising in combination. a. an input-outputterminal means for providing electrical terminations for attachingelectrical circuits; b. a transient protection circuit for protectingsaid audible alarm system against voltage transients and having an inputside connected to said input-output terminal means, and an output side;c. a tone generator circuit for producing an audible tone and having aninput side and an output side including a piezoelectric transducerconnected to said input-output terminal means; and d. a pulsator circuitfor producing pulsations in said audible tone comprising:
 1. a firstNAND gate section of a Quad two-input NAND gate integrated circuitpackage, a first input connected to said output side of said transientprotection circuit, and a second input connected to one side of a firstresistance means;
 2. a second NAND gate section of a Quad two-input NANDgate integrated circuit package, a first input connected to said outputside of said transient protection circuit, a second input connected toan output of said first NAND gate section and to a first side of asecond resistance means, and an output of said second NAND gate sectionconnected to said input side of said tone generator circuit and to afirst side of a capacitance means; and
 3. a second side of said firstresistance means connected to a second side of said second resistancemeans and to a second side of said capacitance means
 2. a second NANDgate section of a Quad two-input NAND gate integrated circuit package, afirst input connected to said output side of said transient protectioncircuit, a second input connected to an output of said first NAND gatesection and to a first side of a second resistance means, and an outputof said second NAND gate section connected to said input side of saidtone generator circuit and to a first side of a capacitance means; and2. A multiple audible alarm system comprising in combination. a. aninput-output terminal means for providing electrical termination forattaching electrical circuits; b. a transient protection circuit forprotecting said audible alarm system against voltage transients andhaving an input side connected to said input-output terminal means, andan output side; c. a tone generator circuit for producing an audibletone and having an input side and an output side including apiezoelectric transducer connected to said input-output terminal means;and d. a ground isolation circuit providing more than one ground path tosaid multiple audible alarm system, a first side connected directly tosaid input-output terminal means, a second side connected directly tosaid input side of said transient protection circuit and to saidinput-output terminal means, and also to said input side of saidtransient protection circuit and to said input output terminal meansthrough a first resistance means, and a third side connected to saidinput side of said tone generator circuit; whereby said piezoelectrictransducer provides pulsating sounds or continuous sounds in response toa precondition of said multiple function alarm system.
 3. a second sideof said first resistance means connected to a second side of said secondresistance means and to a second side of said capacitance means
 3. Amultiple function alarm system according to claim 2 wherein said tonegenerator circuit further includes at least one NAND gate, said NANDgate and said pulsator circuit included as an integrated circuit packageand wherein said third side of said ground isolation circuit isconnected a minus voltage terminal of said integrated circuit packageand to said piezoelectric transducer.
 4. A multiple function alarmsystem acCording to claim 3 wherein said pulsator circuit includes twoNAND gates.
 5. A multiple audible alarm system according to claim 2wherein said input-output terminal means includes: a. a secondtermination connected to said third side of said ground isolationcircuit; b. a second termination connected to said input side of saidtransient protection circuit and also through said first resistancemeans to said first termination; c. a third termination connected tosaid input side of said transient protection circuit; and d. a fourthtermination connected to said of said transient protection circuit, saidsecond side of said ground isolation circuit, and also through a secondresistance means to said third termination.
 6. A multiple audible alarmsystem according to claim 2 wherein said pulsator circuit comprises: a.a first NAND gate section of a Quad two-input NAND gate integratedcircuit package, a first input connected to said output side of saidtransient protection circuit, and a second input to one side of a thirdresistance means; b. a second NAND gate section of a Quad two-input NANDgate integrated circuit package, a first input connected to said outputside of said transient protection means, a second input connected to anoutput of said first NAND gate section and to a first side of a fourthresistance means, and an output of said second NAND gate sectionconnected to said input side of said tone generator circuit and to afirst side of a first capacitance means; and c. a second side of saidthird resistance means connected to a second side of said fourthresistance means and to a second side of said first capacitance means.7. A multiple audible alarm system according to claim 2 wherein: saidpiezoelectric transducer has three electrodes, a first electrode ofwhich is connected to said third side of said ground isolation circuitand said minus voltage terminal of a Quad two-input NAND gate integratedcircuit package; and wherein said tone generator circuit furtherincludes: a. a third NAND gate section of said Quad two-input NAND gateintegrated circuit package, a first input connected to said output sideof said pulsator circuit, a second input connected to a first side of afifth resistance means and to a second electrode of said piezoelectrictransducer, an output connected to a second side of said fifthresistance means and to a first side of a sixth resistance means; b. afourth NAND gate section of said Quad two-input NAND gate integratedcircuit package, a first input connected to said first input of saidthird NAND gate section, a second input connected to said second inputof said third NAND gate section, and an output connected to said outputof said third NAND gate section; and c. a second side of said sixthresistance means connected to a third electrode of said piezoelectrictransducer.
 8. A multiple alarm system according to claim 2 wherein saidground isolation circuit includes first and second diodes, the anodes ofwhich are connected together and to said output side of said tonegenerator circuit and said minus voltage terminal, the same being aterminal of a Quad two-input NAND gate integrated circuit package, acathode of said first diode connected to a first termination of saidinput-output terminal means and through a first resistance means to asecond termination of said input-output terminal means, and a cathode ofsaid second diode connected to said fourth termination of saidinput-output terminal means, through a second resistance means to athird termination of said input-output terminal means, and to said inputside of said transient protection circuit.
 9. A multiple audible alarmsystem according to claim 2 wherein said transient protection circuitcomprises seventh, eighth and ninth resistance means, said seventhresistance means connected between said fourth termination and saidinput side of said pulsator circuit, said eighTh resistance meansconnected between said third termination and a positive voltage terminalof a Quad two-input NAND gate integrated circuit package, and said ninthresistance means connected between said second termination and saidinput side of said pulsator circuit.